Safety device for engines



Nov. 16, 1937. A. o. CARPENTER SAFETY DEVICE FOR ENGINES Filed Sept. 23,1956 2 Sheets-Sheet 1 Q Ev N A Q Wu @m & ww w v Q @Q INV ENTOR Alla/z 06H I S ATTORNEY.

Nov. 16, 1937. A. o. CARPENTER 2,099,556

SAFETY DEVICE FOR ENGINES Filed Sept. 25, 1956 2 Sheets-Sheet 2 INVENTORzfllmzateyoenfen H l S ATTORNEY,

Patented Nov. 16, 1937 UNITED STATES PATENT OFFICE 7 2,009,550 ssr'a'r'rnnvrca roa enemas Application September 23, 1333. Serial No. 132,313

4 Claims.

This invention relates to engines, and more particularly to a safetydevice associated with the pressure lubricating system of an engine.

One object of the invention is to automatically 5 stop the engine whenit is operating under conditions considered unsafe as, for example, whenthe pressure in the lubricating system drops to a value that would betoo low to effectively lubricate the engine.

Another object is to induce a decreasing pressure in thelubricatingsystem and thereby cause operation of the safety device whenever thespeed of the engine exceeds a certain predetermined maximum.

Other objects will be in part obvious and in part pointed outhereinafter.

In the drawings accompanying this specification and in which similarreference numerals refer to similar parts,

Figure 1 is a side elevation, partly in section, of a safety deviceconstructed in accordance with the practice of the invention, and

Figure 2 is a transverse view taken through Figure 1 on the line 22. 1

Referring more particularly to the drawings, 23 designates, in general,a safety device constructed in accordance with the practice of theinvention, 2| a conduit for conveying power medium to an engine to whichthe safety device may be applied, and'22 designates a pump for pumpinglubricant under pressure to the various bearing surfaces of the engine,and which may be connected to be driven by the crank shaft of theengine.

The safety device is mounted, in the present instance, on the casing 23.of a safety valve interposed in the conduit 2| and comprises as anelement a weighted lever 24 for actuating a valve 25 in the casing 23.The valve 25 is loosely guided by ribs 25 in the casing 23 andcooperates with a seat 21 to cut off the flow of steam through theconduit 2|. On the upper surface of the valve 25 is a ng 23 having anoblong slot 23 to accomm ate a pin 33 carried by anarm 3| keyed to arotary shaft 32 in the casing 23. The weighted lever 24 is also mountedon the shaft 32 but is freely rotatable thereon. Adjacent the lever andmounted on the shaft 32, to which it is keyed, is a plate 33 havinglateral projections 34 and 35 respectively overlying and extendingunderneath the lever 24 and so spaced that, the lever is capable of somedegree of movement between the projections.

During the normal operation of the engine the valve 25 is, of course,,inthe open position and plays no part in the control of the flow of steamthrough the conduit, this being effected by other devices, as forexample a hand-controlled valve 36. The valve 25 serves moreparticularly the function of a safety valve adapted to cut 08 the flowof steam to the engine in the event that the pressure of the lubricantin the lubricating system of the engine drops to a value insufflcient tomaintain the various bearing surfaces of the engine in a safelylubricated condition.

The valve 25 is accordingly held open by the lever 24 which in thisposition of the parts bears against the projection 34, and the lever isin turn supported by a latch 31 mounted pivotally upon a rod 33 threadedinto the-casing 23. The latch 31 is in the form of a bell crank of whichan upwardly extending arm 33 carries a lug 43 to form a seat for a pin4| in the lever 24.

The lug 43 is oflset with respect to the vertical plane of the rod 33and a surface 42- on the arm 33 bears against the end of the pin 4| tolimit rotary movement of the latch 31 in the direction of the lever 24.A coil spring 43 is arranged on the rod 33 to maintain the latch 31 insubstantially the correct operative position. One end of the spring maybe affixed to the latch 31 and the other end to a collar 44 afflxed tothe rod 33.

Means are provided for tripping the latch 31 to move it out ofengagement with 'the lever 24. The means illustrated for this purposeconsists of a rod or plate 45 which is vertically slidable in a slot 43of a guide member 41 supported by the casing 23. The plate 45 carries amass 43 of metal which is of sufllcient weight to trip the latch 31 toits releasing position. In the side of the mass 43 is a bar 43 which,when the plate 45 descends in the slot 45, strikes an arm 53 of thelatch member 31 and rocks the latch out of engagement with the pin 4| ofthe lever 24.

The plate 45 is normally supported by a plunger 5| which extendsslidably through an aperture 52 in the guide member 41 and into anaperture 53 in the plate 45. The plunger is pivotally connected to thefree end of an arm 54 of a bell crank 55 mounted on a pivot pin 53 onthe guide member 41. The other arm 51 of the bell crank 55 is connectedto a spring 53 which constantly tends to rock the bell crank 55 in adirection for withdrawing the plunger 5| from the aperture 53. Thetension of the spring 53 may be conveniently adjusted by means of ascrew 53 serving as an anchor for an end of the spring.

By means of the screw 53 the spring 53 may be tensioned to enable it towithdraw the plunger II from the aperture 52 for releasing the weightll. -Normally, however, the spring is rendered' non-effective by thepressure in the lubricating system of the engine. The means employed forthis purpose comprises a casing ll consisting of a pair of plates II andI2 between which is clamped a diaphragm 63 to form a resilient wall fora pressure chamber 84 in the plate 02. The chamber 64 is connected withthe source of lubricant supply under pressure by a conduit ll having abranch conduit 8. connecting it to the discharge pipe 01 of the pump 22.The passage in the conduit it is preferably of considerably smallerdiameter than that in conduit 81 so that no serious reduction inpressure will occur in the lubricating system in the event that thechamber 64 is vented to permit operation of the devices controlling thevalve 25.

On the central portion of the diaphragm 63 is a plate 68 which bearsagainst the end of a pin 68 slidable in the plate 6i. The other end ofthe pin abuts an intermediate portion of the arm 54 of the bell crank 55and the pin 69 thus serves to transmit the thrust of the diaphragm N tothe plunger ii for maintaining it in engagement with the plate 45.

To the end that the plate 45 may be maintained suspended above and innon-contacting relationship with the latch 31 during the starting of theengine, and during which time the pressure in the lubricating system isof insuillcient value to maintain the plunger 5| in engagement with theplate 45, a manually actuated plunger or button I0 is arranged in theguide member 41 and coaxially with the plunger 5| The button I0comprises a head 1i adapted to extend into an enlarged portion 12 of theaperture 53 and a stem ll which projects to the exterior of the guidemember 41 and in convenient position to be actuated into the aperture 53by the attendant.

In order that the safety device may be caused to operate for stoppingthe engine in the event that the engine speed exceeds a predeterminedmaximum said device is provided with means for relieving or removing thepressure in the chamber 04. The means provided for this purpose consistsof a pressure relief device 14 interposed in a conduit 15 connected tothe conduit 65.

The relief device comprises a casing 18 which may be supported by thepump 22 and has a bore 11 to accommodate a valve 18 of the plunger type.The valve has an annular external groove 19 to afford communicationbetween the conduit 15 and a conduit which may lead to the lubricantsupply reservoir.

The ends of the valve I8 project exteriorly of the casing 18 and to oneend is aflixed, as by means of a screw 8i, a seat 82 for a compressionspring 83 of which an end seats against the outer surface of the casing18. The valve 18 is further provided with a notch 84 for engagement witha spring-pressed detent 85 which serves to hold the valve I8 in positionto maintain the groove 19 out of registry with the conduits l5 and It.On the opposite end of the valve 18 isa head 86 of which the outersurface 8'! is of convex shape.

The valve preferably lies in the horizontal plane of the shaft 88 of thepump 22 and the shaft 88 carries a flange 88 having a bore 90 to guidethe stem 9| of a weight or plunger 92 which normally seats against theside of the flange 891 The outer surface 93 of the weight is convex andon the opposite end of the stem 9| is a seat 04 for an end of a spring95 in a recess 9! in the flange I. and

aooasso acting to resist the centrifugal force acting upon the weight82.

The operation of the device is as follows: Before setting the engine inoperation the weighted plate 45 is lifted to a position in which theaperture 53 coincides with the head II of the button II. The button IIis then pressed into engagement with the plate to support it above thelatch 31, it being understood, of course, that under these conditionsthe pressure of the lubricant in the chamber 64 will be of insuflicientvalue to maintain the plunger ii in engagement with the plate 45.

After the weighted plate 45 is mounted on the button It the lever 24 maybe raised to open the valve 25 and the spring I! will then rock thelatch into position to place the lug 40 beneath the pin 4| forsupporting the lever in that position. The valve 36 may then be openedto supply steam to the engine and as the speed of the engine increasesand the pressure in the lubricating system, and acting against thediaphragm 63, approaches maximum the diaphragm will move the plunger 5|and push the button I0 out of engagement with the plate 45. The weightof the plate 45 will then be transferred to the plunger 5|.

The plunger 5| stays in this position as long as the pressure in thelubricating system remains of the value required to assure thoroughlubrication of the engine. However, should the pressure in thelubricating system drop below the force exerted by the spring 58 thespring will rock the bell crank it and withdraw the plunger 5| from theaperture 53 and release the plate 45. The plate 45 will then drop uponthe latch 31 and rock it about the rod 38, thereby disengaging the lugfrom the pin 4|. The lever 24 wfll then drop and move the valve 25 tothe seat 21 to cut off the admission of steam to the engine, which willthen come to rest.

In practice, the spring BI is so adjusted that it will act to releasethe weighted plate 45 while the pressure in the lubricating system isstill well within the range of safety so that the engine will be broughtto restwhile its bearing surfaces are still thoroughly lubricated. Noharm will, therefore, be caused to any part requiring lubrication eventhough the pressure of the lubricant would .be of insufllcient value towarrant further prolonged operation of the engine.

During the normal operation of the engine, the valve It occupies aposition in which the spring 83 is compressed and the groove 19 is outof registration with the conduits I5 and 80. The valve is held thus bythe detent 85. Also, the weight 92 is then pressed against the side ofthe flange 89 by the spring 95. In the event, however, that the speed ofthe engine and, therefore, of the pump 22 exceeds a certainpredetermined maximum the weight 92 is actuated centrifugally outwardlyand. on striking the convex surface 81 of the button 86, releases thevalve I! from the detent 85. The spring 83 then shifts the valve 18 to aposition in which the groove 19 registers with the conduits l5 and 80.In this way the pressure of the lubricant in the chamber 84 and in theconduits connecting said chamber with the relief device It is reduced toa value below that exerted by the spring 58 which will then disengagethe plunger II from the plate 45 and the weighted plate will drop, inthe manner previously described, to set the various elements inoperation for closing the valve 2!.

I claim:

1. In a safety device, the combination of an engine having a pressurelubricating system and MIN a conduit for conveying power medium to theengine, of a valve to cut oil the flow of power medium to the engine andhaving a lever. actuating with the actuating means. means actingresponsively to a decreasing pressure in the lubricating system to movethe support out oi supporting position to enable the actuating means toclose the valve, and means acting in response to a predetermined maximumspeed oi the engine to cause operation of the last mentioned means.

2. In a safety device, the combination of an engine having a pressurelubricating system and a conduit for conveying power medium to theengine, of a valve to cut oil the iiow of power medium to the engine, aweighted lever on the valve. actuating means movable by gravity againstthe weighted lever for closing the valve, a movable support for theactuating means, pressure responsive means subjected to the pressure ofthe lubricant tor normally maintaining the movable support in engagementwith the actuating means, means acting responsively to a decreasingpressure in the lubricating system to move the support out of supportingposition to enable the actuating means to close the valve, a reliefvalve tor the pressure responsive means, and means acting in response tothe speed of the engine for opening the relief valve.

3. The combination with an engine having a .enslne.

means for releasing the seat irom thefleverg'a manually shiitablesupport for the trip means. a I

second support actuated by lubricant-under pressure to displace themanually shii'table "support-{ for holding the trip means. and means fordisenaging ssidsecond support from the trip-means.

to a predetermined value, thereby enabling the? g 31-" pressurelubricant system, of a valve to out ofl the ilaow of power medium to theengine. a'vleight ed lever to actuate the valve, a shiitable seat-tor gY the lever to normally hold the valve open, trip 'l'o I y when thepressure in the lubricating system drops v trip means to disengage theseat from the weight ed lever and the weighted lever to close the valvefor cutting oi! the flow of power medium to the:

4. The combination with an engine having a pressure lubricant system.voi a 'valve to out 01! the flow of power medium to the engine; aweighted lever to actua'telthe valve, 9; shiitable seat for the lever tonormally hold the valve open, trip means for releasing the seat fromthe, lever, a button to support the trip means and'being manuallyactuated into engagement with the trip means, a plunger actuated bylubricant under pressure to displace the button and to support the tripmeans,

and a spring for disengaging the plunger from the trip means when thepressure in the lubricating system drops to a predetermined value.

thereby enabling the trip means to disengage the seat from the weightedlever and the weighted lever to close the valve for cutting oi! the nowoi power medium to the engine.-

. v ALLAN O. CARPENTER.

